What are Packaged Terminal AC?
Packaged terminal air conditioning units, PTACs, are typically selected where individual zones have an outside wall and are conditioned separately with individual occupant control. PTACs are well suited to hotels, motels, nursing homes and apartments. As the name implies, a single package contains all the components of an air-cooled refrigeration and air-handling system in an individual package.
Units are designed for through-the-wall installation, with decorative outdoor grilles as an option. Units are also available with various heating options-electric resistance or hydronic. Other variations include the Packaged Terminal Heat Pump (PTHP).

Why PTAC is not better than Mini Split AC ?
The system tends to have higher maintenance costs because of multiple compressors and fans.
Routine service in the occupied space required to change filters and clean coils.
The system is only applicable to perimeter zones.
Noise levels vary considerably and the system is generally too loud for critical applications.
PTAC's are not as energy efficient as Mini Split Acs. Humidification, when required, must be supplied by a separate system.

What is the difference between a PTHP heat pump and a PTAC air conditioner ?
Looking from the outisde, its a bit difficult to say if it is an air conditioner with primary electric heat, or a heat pump air conditioner with secondary electric heat. A heat pump air conditioner describes a unit that offers the heat pump mode of heating. The heat pump mode of heating is the most efficient source of heat. Both PTAC and PTHP units have electric strip heaters. The electric heater is the only source of heat on a PTAC unit, it’s a back-up source of heat on a PTHP. A heat pump can’t generate heat easily when it’s really cold outside. The back-up electric heat will be energized when the PTHP unit can no longer keep up in the heat pump mode.

Are PTAC units better than Central AC or ductless split systems?
Although not usually the ideal choice PTAC units are considered for specific applications only. PTAC's are mainly seen in hotels/motels for individualized control system, but they are being now replaced with ductless split systems instead as ductless split ac units are more energy efficient and whisper quiet. The initial cost is typically less than a central system adapted for room occupant control. Building space is conserved since ductwork and mechanical rooms are not needed. Installation is easy. It's almost a matter of wiring the unit in a hole in the wall.
Old or malfunctioning units may be quickly and easily replaced with a spare chassis.
Numerous control options.
Well-suited to spaces requiring many individual temperature control zones.